Parasites and their Belations to other Animals. 91 



Dr Burnett has also established to his satisfaction the fol- 

 lowing facts : — 1. That although there are single species of 

 parasites peculiar to particular animals, there are others 

 which are found in different species of the same genus, as is 

 the case in the parasites living on birds of the genus Larus 

 (gulls), and the diurnal birds of prey. 2. The parasites of 

 the human body confine themselves strictly to particular 

 regions ; when they are found elsewhere it is the result of 

 accident. Thus, the Pediculus capitis live in the head ; the 

 P. vestimenti upon the surface of the body ; the P. tabescen* 

 tium on the bodies of those dying with marasmus ; and 

 the Fhthirius inguinalls about the groins, armpits, mouth, 

 and eyes, or the homologous parts of the body. From an 

 examination of the structure of these animals, Dr Burnett is 

 of the opinion that they should be placed in an order by 

 themselves, closely allied to the Insecta; they number about 

 250 species, the Mundibulate parasites occupying the highest, 

 and the Haustellate the lowest position in the order. 



Dr Burnett also stated that he had recently found vegetable 

 parasites in the human ovum. They belonged to a species 

 of Conferva similar to the yeast plant. They appear in trip- 

 lets, or by twos, and were about one 4000th of an inch in 

 diameter. It was difficult to account for their presence in 

 such a situation, as their spores would be too large to be 

 deposited from the circulation by passing through the walls 

 of the blood-vessels. — The American Annual of Scientific 

 Discovery for 1851, p. 340. 



On Parasitic Life. — Dr J.Leidy has established the fact, that 

 cryptogamic vegetables exist, as a normal condition, in the 

 interior of several species of healthy animals. He describes 

 three new genera of entophytes, — Euterobrus, Cladophytum^ 

 and Arthromitus, — all being confervoid or mycodermatoid. 

 All are found growing from the mucous membrane of the 

 small intestine and commencement of the large intestine of 

 Julus marginatus (Say), and from entozoa inhabiting these 

 cavities in the same animal. They were uniformly found in 

 116 examinations of animals of this species, made immediately 

 after death. In one instance, an arcaris, three lines long, 



